1. Field of the Invention
The present invention pertains to apparatus for maneuvering marine vessels in bodies of water. More particularly, the present invention relates to drive apparatus for maneuvering vessels through water wherein the drive mechanism is at least partially retractable above the water line when not in use.
2. Brief Description of Prior Art
In addition to an inboard motor rotating an elongate drive shaft to turn a propeller for propelling boats and ships of all sizes, two other types of mechanical drive mechanisms are available, at least for small craft. These include outboard motors, in which a motor supports a propeller assembly suspended on a rigid mounting extending down into the water, wherein rotation of the entire motor causes rotation of the propeller assembly to steer the craft. Inboard-outboard motors feature a motor permanently mounted inboard and linked to a propeller assembly mounted on an arm extending downwardly below the water line and turnable for steering. Outboard motors may be tilted so that the suspended propeller assembly may be lifted out of the water. The arm supporting the propeller driven by an inboard-outboard motor may be rotated to lift the propeller out of the water. However, in the case of a standard inboard motor, the propeller is mounted on the underwater drive shaft and is not readily accessible from above the water line.
An outboard motor does not have the advantages of ease of accessibility and wide range of sizes featured by an inboard motor, and is further hampered with the hazards and inconvenience of being supported on the stern transom of a boat. An inboard-outboard motor may be larger in size than an outboard motor, but provides a drive linkage that extends through the stern transom of the boat to be angled downwardly with the propeller submerged. On the other hand, the propeller assembly of an inboard motor may not be readily retrieved above the water line for servicing and removal of debris, for example. Additionally, it is inconvenient under other circumstances to have the propeller assembly below the water line, such as in the case of vessels under sail wherein the auxiliary motor is not being used to propel the craft, during which time the propeller assembly may provide a considerable drag against movement of the vessel through the water.
It is desirable and advantageous to have available the convenience and other advantages of an inboard motor coupled with the convenience and other advantages of a retractable drive assembly, and such are provided by the present invention.